This post is going to be rather slapdash from the perspective of statistics. I imagine that some of my readers will have fun looking up the statistics, perhaps some just in order to tell me I'm out to lunch, perhaps some to support my thesis.
I was inspired to think of this thesis by this article by Fr. Robert McTeigue. He is a good raconteur. His anecdotes about how he made students turn pale by telling them that birth control could fail and that condoms do not always protect against disease are amusing, in a dark way, which is probably exactly what he intended.
Let's start with the acknowledged fact that the sexual left's vaunted "safe sex" procedures are not terribly close to perfectly safe. Fr. McTeigue has some of the details. Others can be found. This is even more true for prevention of STDs than for prevention of pregnancy. If one uses a LARC, which is the leftist "gold standard" in pregnancy prevention, one can in essence temporarily sterilize oneself pretty darned effectively. (LARCs are IUDs, long-acting sterilization injections, or birth control implants under the skin.) STD prevention, on the other hand, is more a matter of reducing the rate of infection spread within a population if condoms are used according to protocols. (Keep comments family friendly, please, if commenting on this part of the post.) It is actually irresponsible, as Fr. McTeigue points out, to tell an individual that condoms make sexual intercourse "safe" from the spread of disease. At most, they make it safer, and even a few liberals have acknowledged this, though as far as I can tell, the phrase "safer sex" as opposed to "safe sex" never really took off.
But that reduction is worth it to the sexual left, and they will ardently promote "safe sex" as "responsible behavior" while not acknowledging that promiscuity itself is irresponsible, both emotionally and physically. This point has been emphasized by Dr. Miriam Grossman, who saw the wreckage of the hookup culture up close, along with the utter failure of the medical establishment to talk about it honestly.
Now let's turn to the attitude of the sexual left to Natural Family Planning. I want to emphasize here that my intention is not to take a particular position on the intrinsic rightness or wrongness of artificial contraception but rather to make a point about the strange disconnect between leftist attitudes towards disease and babies.
When couples use NFP according to protocols, this reduces the number of unexpected pregnancies within the population using the protocols. That is just true. It's even true if one sticks just to the use of NFP protocols for fertile, non-breastfeeding women and if one acknowledges that it becomes much harder to use NFP during breastfeeding (when ovulation tends to be suppressed and hence more random) or during perimenopause. People in those latter situations must either follow much more difficult protocols, resulting in what could be an unhealthy lack of intercourse for the relationship, or else "take their chances" to a larger extent. Nonetheless, since those are the less fertile periods of the woman's life by definition, it remains true that, if all non-celibate couples followed even the general protocols of NFP, with charting and periodic abstinence, there would be a lot fewer unexpected pregnancies in the world. (The simple invention of the battery operated oral thermometer, which can give basal body temperature, taken first thing in the morning, to the nearest tenth of a degree, has all by itself made NFP a good deal more scientific than it was before that invention.)
Nonetheless, it remains true that there are limitations in the method, particularly if a couple does not wish to remain abstinent during the entire earlier portion of the woman's monthly cycle. Charting is, to some degree, a matter of gathering data for an informed induction over time. In any given month discovering when ovulation has taken place has (as a guide to action) something of the paradoxical nature of saying, "When you come to the last bus stop on the line, get off at the bus stop just before that one." So unexpected pregnancies still do happen even to couples following protocols carefully, especially for women with irregular cycles.
So, as with the use of a condom to prevent STDs, it is not possible to say truthfully to a particular couple, "This method will infallibly avoid what you are trying to avoid for you as individuals." Rather, the effect is on a larger scale--fewer unexpected pregnancies over the course of that couple's fertile years, within the whole population following the method, etc.
But notice the difference in the left's attitudes. Rather than lauding NFP as "responsible," they scorn it as irrelevant and stupid. It just isn't enough that it reduces unexpected pregnancies in a sexually active relationship. No, we must be able to offer the individual and the couple a virtual guarantee that, whatever else happens, no baby will result from this sexual act.
The variation in the ardor of promotion of condoms vs. NFP and the negative vs. positive attitudes leads me to the following conclusion: The sexual left considers it more important to avoid the conception of a baby than to avoid contracting a humiliating and possibly life-threatening disease.
Makes you think.